LED strip with potentiometer howto

Discussion in 'The Projects Forum' started by zogorean, Oct 2, 2014.

  1. zogorean

    Thread Starter New Member

    Jan 12, 2013
    11
    0
    Hello all.
    I just purchased a 3m long LED strip and mounted it behind the bed hoping it would be a nice and cousy lightsource. However it shines too bright, and therefore I want to be able to adjust the brightness. The transformer outputs 12v 2amp max.

    Can someone tell me what to do? Many thanks in advance.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,451
    3,370
    You need a light dimmer circuit that uses pulse width modulation (PWM).

    A 555 timer circuit driving a transistor would be one solution.
     
  3. #12

    Expert

    Nov 30, 2010
    16,346
    6,835
    Here's what I have in stock. Change the op-amp to the LMC6442 and feed this 5 volts for a power supply.
     
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,813
    1,105
    I don't see how the circuit in post #3 provides PWM? The output from the 555 is constant-width pulses and Q2, although pulsed, is never switched fully on.
     
  6. #12

    Expert

    Nov 30, 2010
    16,346
    6,835
    Maybe that circuit is worthless. It's just something I picked up on AAC.
    Then again, if O.P. never responds, it doesn't matter. :rolleyes:
    If he does, I'll try to fix it.
     
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